Display device

ABSTRACT

A display device includes a display panel including a substrate, pixels provided on the substrate, and first lines connected to the pixels, the display device having a bending area where the display panel is bent. The display panel also includes a chip on film overlapping with a portion of the display panel and having second lines, an anisotropic conductive film provided between the chip on film and the display panel connecting the first lines and the second lines, and a coating layer covering the bending area and one end of the chip on film. In such a device, lines of the chip on film may be prevented from being corroded as they may be spaced apart from an edge of an insulating film.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2016-0082847, filed on Jun. 30, 2016, which is herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND Field

Exemplary embodiments relate to a display device, and more particularly,to a display device that includes a chip on film.

Discussion of the Background

An organic light emitting display device includes two electrodes and anorganic light emitting layer disposed between the two electrodes,wherein an electron injected from one of the electrodes and a holeinjected from the other one of the electrodes are coupled to each otherin the organic light emitting layer, forming an exciton which emitslight while releasing energy.

Such an organic light emitting display device may be driven by a signalfrom a driver connected through a chip on film (COF).

The above information disclosed in this Background section is only forenhancement of understanding of the background of the inventive concept,and, therefore, it may contain information that does not form the priorart that is already known in this country to a person of ordinary skillin the art.

SUMMARY

Exemplary embodiments provide a display device which prevents thecorrosion of the lines of a chip on film.

Additional aspects will be set forth in the detailed description whichfollows, and, in part, will be apparent from the disclosure, or may belearned by practice of the inventive concept.

An exemplary embodiment discloses a display device that includes adisplay panel including a substrate, pixels provided on the substrate,and first lines connected to the pixels, the display device having abending area where the display panel is bent. The display panel alsoincludes a chip on film overlapping with a portion of the display paneland having second lines, an anisotropic conductive film provided betweenthe chip on film and the display panel connecting the first lines andthe second lines, and a coating layer covering the bending area and oneend of the chip on film.

The foregoing general description and the following detailed descriptionare exemplary and explanatory and are intended to provide furtherexplanation of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the inventive concept, and are incorporated in andconstitute a part of this specification, illustrate exemplaryembodiments of the inventive concept, and, together with thedescription, serve to explain principles of the inventive concept.

FIG. 1 is a perspective view illustrating a display device according toan exemplary embodiment.

FIG. 2 is a plan view illustrating the display device of FIG. 1.

FIG. 3 is a equivalent circuit diagram of a case where a pixel is alight emitting device according to an exemplary embodiment.

FIG. 4A is an exploded plan view of portion A1 of FIG. 2 where a displaypanel and a chip on film are connected to each other in a display deviceaccording to an exemplary embodiment.

FIG. 4B is a cross-sectional view taken on line IV-IV′ of FIG. 4A.

FIG. 5A is a plan view illustrating the display panel in FIG. 4A.

FIG. 5B is a plan view illustrating the chip on film in FIG. 4A.

FIG. 6 is a cross-sectional view illustrating a display device accordingto an exemplary embodiment.

FIGS. 7A, 7B, and 7C are cross-sectional views illustrating a process ofattaching a display panel and a chip on film sequentially in a displaydevice according to an exemplary embodiment.

FIGS. 8A and 8B are plan views illustrating second pads of a chip onfilm according to an exemplary embodiment.

FIG. 9 is a view illustrating a display device according to an exemplaryembodiment.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various exemplary embodiments. It is apparent, however,that various exemplary embodiments may be practiced without thesespecific details or with one or more equivalent arrangements. In otherinstances, well-known structures and devices are shown in block diagramform in order to avoid unnecessarily obscuring various exemplaryembodiments.

In the accompanying figures, the size and relative sizes of layers,films, panels, regions, etc., may be exaggerated for clarity anddescriptive purposes. Also, like reference numerals denote likeelements.

When an element or layer is referred to as being “on,” “connected to,”or “coupled to” another element or layer, it may be directly on,connected to, or coupled to the other element or layer or interveningelements or layers may be present. When, however, an element or layer isreferred to as being “directly on,” “directly connected to,” or“directly coupled to” another element or layer, there are no interveningelements or layers present. For the purposes of this disclosure, “atleast one of X, Y, and Z” and “at least one selected from the groupconsisting of X, Y, and Z” may be construed as X only, Y only, Z only,or any combination of two or more of X, Y, and Z, such as, for instance,XYZ, XYY, YZ, and ZZ. Like numbers refer to like elements throughout. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

Although the terms first, second, etc. may be used herein to describevarious elements, components, regions, layers, and/or sections, theseelements, components, regions, layers, and/or sections should not belimited by these terms. These terms are used to distinguish one element,component, region, layer, and/or section from another element,component, region, layer, and/or section. Thus, a first element,component, region, layer, and/or section discussed below could be termeda second element, component, region, layer, and/or section withoutdeparting from the teachings of the present disclosure.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper,” and the like, may be used herein for descriptive purposes, and,thereby, to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the drawings. Spatiallyrelative terms are intended to encompass different orientations of anapparatus in use, operation, and/or manufacture in addition to theorientation depicted in the drawings. For example, if the apparatus inthe drawings is turned over, elements described as “below” or “beneath”other elements or features would then be oriented “above” the otherelements or features. Thus, the exemplary term “below” can encompassboth an orientation of above and below. Furthermore, the apparatus maybe otherwise oriented (e.g., rotated 90 degrees or at otherorientations), and, as such, the spatially relative descriptors usedherein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof.

Various exemplary embodiments are described herein with reference tosectional illustrations that are schematic illustrations of idealizedexemplary embodiments and/or intermediate structures. As such,variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments disclosed herein should not beconstrued as limited to the particular illustrated shapes of regions,but are to include deviations in shapes that result from, for instance,manufacturing. Thus, the regions illustrated in the drawings areschematic in nature and their shapes are not intended to illustrate theactual shape of a region of a device and are not intended to belimiting.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure is a part. Terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and will not be interpreted in anidealized or overly formal sense, unless expressly so defined herein.

FIG. 1 is a perspective view illustrating a display device according toan exemplary embodiment of the present disclosure, and FIG. 2 is a planview illustrating the display device of FIG. 1.

Referring to FIGS. 1 and 2, a display device according to an exemplaryembodiment includes a display panel DP, and a driving circuit boardconnected to the display panel DP.

According to an exemplary embodiment, the display panel DP includes asubstrate SUB, pixels PXL provided on the substrate SUB, and lines LPconnected to the pixels PXL.

The substrate SUB includes a display area DA and a non-display area NDAprovided in at least one side of the display area DA.

The substrate SUB may have a generally quadrangular shape, moreparticularly, a rectangular shape. In an exemplary embodiment, thesubstrate SUB may include a pair of short sides parallel to each otherin a first direction DR1 and a pair of long sides parallel to each otherin a second direction DR2. In the present embodiment, for convenience ofexplanation, the sides of the substrate SUB are indicated as four sides,that is, a first side S1 to a fourth side S4, connected sequentiallystarting from one short side.

However, the shape of the substrate SUB is not limited thereto, and mayvary. For example, the substrate SUB may be provided in various shapessuch as a closed polygonal shape that includes a side made of a straightline, a circle or an ellipse that includes a side made of a curve, asemi-circle or a semi-ellipse that includes a side made of a straightline and a side made of a curve, etc. In an exemplary embodiment, in thecase where the substrate SUB has a side made of a straight line, atleast a portion of a corner having an angular shape may be made of acurve. For example, in the case where the substrate SUB has arectangular shape, a portion where straight sides adjacent to each othermeet may be replaced by a curve having a certain curvature. That is, avertex portion of the rectangular shape may consist of a curved side ofwhich both ends adjacent to each other are each connected to twostraight side, the curved side having a certain curvature. The curvatureof the curved side may vary depending on its position. For example, thecurvature may vary depending a position where the curve starts and alength of the curve, etc.

The display area DA is an area where a plurality of pixels PXL areprovided, and thus where images may be displayed.

The display area DA may be provided in a shape corresponding to theshape of the substrate SUB. For example, the display area DA may beprovided in various shapes such as a closed polygonal shape thatincludes a side made of a straight line, a circle or an ellipse thatincludes a side made of a curve, a semicircle or a semiellipse thatincludes a side made of a straight line and a side made of a curve,etc., just as the shape of the substrate SUB. In an exemplaryembodiment, in the case where the display area DA has a side made of astraight line, at least a portion of a corner having an angular shapemay be made of a curve.

The pixels PXL may be provided on the display area DA of the substrateSUB. Each pixel PXL is a minimum unit for displaying an image, and thepixel PXL may be provided in plural. The pixels PXL may output a whitelight and/or a color light. Each pixel PXL may output one of colors suchas red, green and blue, etc., but without limitation, that is, eachpixel PXL may instead output one of colors such as cyan, magenta, andyellow, etc.

The pixel PXL may be a light emitting device that includes an organiclight emitting layer. However, the pixel PXL may be realized in variousforms such as a liquid crystal device, an electrophoretic device, or anelectro-wetting device, etc.

FIG. 3 is an equivalent circuit diagram illustrating the case where thepixel PXL is a light emitting device according to an exemplaryembodiment.

Referring to FIG. 3, each pixel PXL includes a thin film transistorconnected to lines, a light emitting device EL connected to the thinfilm transistor and a capacitor Cst.

The thin film transistor may include a driving thin film transistor TR2for controlling the light emitting device, and a switching thin filmtransistor TR1 for switching the driving thin film transistor TR2.Although it is explained in the present exemplary embodiment that onepixel PXL includes two thin film transistors TR1, TR2, this is not meantas a limitation That is, one pixel PXL may be provided with one thinfilm transistor and one capacitor, or one pixel PXL may be provided withthree or more thin film transistors and two or more capacitors. Forexample, one pixel may include seven thin film transistors, lightemitting devices, and storage capacitors.

The switching thin film transistor TR1 includes a gate electrode, asource electrode and a drain electrode. In the switching thin filmtransistor TR1, the gate electrode is connected to a gate line GL, andthe source electrode is connected to a data line DL. The drain electrodeis connected to a gate electrode of the driving thin film transistorTR2. The switching thin film transistor TR1 transmits a data signalbeing applied to the data line DL to the driving thin film transistorTR2 according to a scan signal being applied to the gate line.

The driving thin film transistor TR2 includes the gate electrode, asource electrode and a drain electrode. In the driving thin filmtransistor TR2, the gate electrode is connected to the switching thinfilm transistor TR1, the source electrode is connected to the drivingvoltage line DVL, and the drain electrode is connected to the lightemitting device EL.

The light emitting device EL may include a light emitting layer, and afirst electrode and a second electrode facing each other with the lightemitting layer disposed therebetween. The first electrode may beconnected to the drain electrode of the driving thin film transistorTR2. The second electrode may be connected to a power line (notillustrated) to be supplied with a common voltage. The light emittinglayer may or may not emit light according to an output signal of thedriving thin film transistor TR2, thereby displaying an image. The lightbeing emitted from the light emitting layer may vary depending on thematerial of the light emitting layer, for example, the light may be acolor light or a white light.

The capacitor Cst may be connected between the gate electrode and thesource electrode of the driving thin film transistor TR2, and may beconfigured to charge and maintain a data signal being input into thegate electrode of the driving thin film transistor TR2.

Referring to FIGS. 1, 2, and 3, a plurality of the pixels PXL may beprovided, arranged in a matrix form along a line extending in a firstdirection DR1 and a row extending in a second direction DR2. However,the arrangement of the pixels PXL is not limited to the aforementioned,and may vary. For example, the pixels PXL may be arranged in a linedirection, or in a direction slanted against the line direction.

The non-display area NDA is an area that is not provided with the pixelsPXL, and thus does not display an image.

The non-display area NDA may be provided with lines LP connected to thepixels PXL, and a driver connected to the lines LP and configured todrive the pixels PXL.

The lines LP may be connected to the pixels PXL, and provide a signal toeach of the pixels PXL. The lines LP may include a gate line GL, a dataline DL, a driving voltage line DVL and a power line, etc. The lines LPmay further include other lines if necessary.

The lines LP may be provided to extend across the display area DA andthe non-display area NDA.

The lines LP are connected to the driver (not illustrated). The driverprovides a signal to each of the pixels PXL through the lines LP, andcontrols operations of each pixel PXL, accordingly.

The driver may include a gate driver (not illustrated) that provides ascan signal to each of the pixels PXL through a scan line, a data driver(not illustrated) that provides a data signal to each of the pixels PXLthrough a data line, and a timing controller (not illustrated) thatcontrols the gate driver and the data driver.

In an exemplary embodiment, the gate driver may be mounted directly onthe substrate SUB. In the case of mounting the gate driver directly onthe substrate SUB, it may be possible to form the gate driver togetherin the process of forming the pixels PXL. However, the position ormethod for providing the gate driver is not limited to theaforementioned, that is, the gate driver may either be provided on thesubstrate SUB in a chip on glass form, or the gate driver may be mountedon a printed circuit board PCB that will be explained hereinafter andthen connected to the substrate SUB through a connecting member.

In an exemplary embodiment, the data driver may be mounted directly onthe substrate SUB, but there is no limitation thereto, that is, the datadriver may be formed in a separate chip and then connected to thesubstrate SUB. In an exemplary embodiment, in the case of forming thedata driver in a separate chip to be connected to the substrate SUB, itis possible to form the data driver in a chip on glass, in a chip onfilm COF or in a printed circuit board PCB that will be explainedhereinafter, and then connect the same to the substrate SUB.

In the present exemplary embodiment, the data driver is exemplified asone that is produced in a chip on film COF form and connected to thesubstrate SUB.

In an exemplary embodiment, the non-display area NDA may further includean is additional area ADA protruding from a portion of the non-displayarea NDA. The additional area ADA may be protruding from the sidesforming the non-display area NDA. In the present exemplary embodiment,the additional area ADA is exemplified as one protruding from one of theshort sides of the substrate SUB. However, the additional area ADA maybe configured to protrude from one of the long sides of the additionalarea ADA instead, or to protrude from two or more of the four sides ofthe additional area ADA. In an exemplary embodiment, the additional areaADA may be provided with the data driver or may be connected to the datadriver, but there is no limitation thereto, that is, other variouselements may be disposed in the additional area ADA.

In an exemplary embodiment, the display device of the present disclosuremay partially have flexibility, so that it may be bent in the portionhaving flexibility. That is, the display device may include a bendingarea BA having flexibility and bent in one direction, and flat areasFA1, FA2 that are provided in at least one side of a foldable area andthat are not bent but are flat. The flat areas FA1, FA2 may or may nothave flexibility.

In the present exemplary embodiment, the bending area BA is exemplifiedas being provided in the additional area ADA. In an exemplaryembodiment, there may be provided a first flat area FA1 and a secondflat area FA2 spaced apart from each other with the bending area BAdisposed therebetween, and the first flat area FA1 may include thedisplay area DA. In an exemplary embodiment, the bending area BA may bespaced apart from the display area DA.

In an exemplary embodiment, the first flat area FA1 and the second flatarea FA2 may be spaced apart from each other with the bending area BAdisposed therebetween. The display panel DP may be bent in the bendingarea BA, and accordingly, the first flat area FA1 and the second flatarea FA2 may be arranged parallel to each other.

Assuming the line by which the display device is bent is a bending line,the bending line is provided in the bending area BA. The term “bending”is used to mean that a shape is not fixed but may be transformed fromits original shape to another shape, for example, being folded, curvedor rolled up like a scroll along two or more certain lines, i.e., thebending line. Therefore, in the present exemplary embodiment, thedisplay device is bent such that one surface of one flat areas FA1 andone surface of the other flat area FA2 face each other, but there is nolimitation thereto, that is, the display device may be bent such thatthe surfaces of the two flat areas form a certain angle against eachother, for example, an acute angle, a right angle or an obtuse angle.

In an exemplary embodiment, the additional area ADA may subsequently bebent by the bending line, in which case a width of a bezel may bereduced as the additional area ADA is bent.

The driving circuit board is provided with a driver, and the drivingcircuit board provides a signal to each of the pixels PXL through thelines LP. Accordingly, the driving circuit board may control operationsof each of the pixels PXL, and thus the driving circuit board mayinclude the gate driver that provides a scan signal to each of thepixels PXL, the data driver that provides a data signal to each of thepixels PXL, and the timing controller that controls the gate driver andthe gate driver. However, as mentioned above, the gate driver and thedata driver may be mounted at various locations, for example, in thedisplay panel DP.

The driving circuit board may include a chip on film COF connected tothe display panel DP. Further, the driving circuit board may furtherinclude a printed circuit board PCB connected to the chip on film COF.

The chip on film COF may process various signals being input from theprinted circuit board PCB and output the processed signals towards thedisplay panel DP. For this purpose, one end of the chip on film COF maybe attached to the display panel DP, and another end of the chip on filmCOF, that is opposite to said one end may be attached to the printedcircuit board PCB. Explanation on the connection relationship betweenthe chip on film COF and the display panel DP will be made later on.

On the printed circuit board PCB, various driving circuits such as atiming driver and the like may be mounted, and the printed circuit boardPCB may output various signals received from the driving circuitstowards the chip on film COF. Examples of the printed circuit board PCBthat may be used herein include a flexible printed circuit board FPCB.

The printed circuit board PCB may be disposed on one surface or on arear surface of the display panel DP. Generally, a display panel DPdisplays an image on its front surface, in which case the rear surfaceof the display panel DP becomes an area that cannot be seen by a user.Therefore, in order to maximize space efficiency and hide the elementsthat need not be seen by the user, the printed circuit board PCB may bedisposed on the rear surface of the display panel DP. However, this isjust an example, that is, the printed circuit board PCB may be disposedon a side surface of the display panel, or instead, the printed circuitboard PCB may be formed integrally with the chip on film COF.

FIG. 4A is an exploded plan view of A1 portion of FIG. 2 where thedisplay panel u) DP and the chip on film COF are connected to each otherin the display device according to an exemplary embodiment of thepresent disclosure. FIG. 4B is a cross-sectional view taken on lineIV-IV′ of FIG. 4A. FIG. 5A is a plan view of the display panel DP inFIG. 4A, and FIG. 5B is a plan view of the chip on film COF in FIG. 4A.

Referring to FIGS. 2, 3, 4A, 4B, 5A, and 5B, the display deviceaccording to an exemplary embodiment includes the display panel DP, thechip on film COF that partially overlaps with the display panel DP, ananisotropic conductive film ACF provided between the chip on film COFand the display panel DP, the bending area BA (see FIG. 1) in which thedisplay panel DP is bent, and a coating layer CL that covers the one endof the chip on film COF.

In an exemplary embodiment, the display panel DP is provided with lines,and the chip on film COF is also provided with lines connected to thelines of the display panel DP, and thus, for convenience of explanation,hereinafter, the lines of the display panel DP will be referred to asfirst lines L1, and the lines of the chip on film COF will be referredto as second lines L2.

The display panel DP may have the substrate SUB, the pixels PXL (see toFIG. 2) provided on the substrate, and the first lines L1 connected tothe pixels PXL.

The substrate SUB may be made of an insulating material such as glassand resin, etc. Additionally, the substrate SUB may be made of amaterial having flexibility so that it may be bent or folded, and thesubstrate SUB may have a structure of a single layer or a structure ofmultiple layers.

For example, the substrate SUB may include at least one of polystyrene,polyvinyl alcohol, polymethyl methacrylate, polyethersulfone,polyacrylate, polyetherimide, polyethylene naphthalate, polyethyleneterephthalate, polyphenylene sulfide, polyarylate, polyimide,polycarbonate, triacetate cellulose and cellulose acetate propionate.However, the material forming the substrate SUB may vary. For example,the substrate SUB may be made of fiber reinforced plastic FRP as well.

The pixel PXL may be a light emitting device that includes an organiclight emitting layer, but without limitation, that is, the pixel PXL maybe realized in various forms such as a liquid crystal element, anelectrophoretic element, and an electro-wetting device, etc.

In the present exemplary embodiment, the pixels PXL are provided aslight emitting devices EL that include the thin film transistor TR1,TR2, a light emitting device EL connected to the thin film transistorTR1, TR2, and the capacitor Cst. The thin film transistor TR1, TR2, thelight emitting device EL and the capacitor Cst may be realized invarious forms using an insulating layer, a conductive layer, asemiconductor layer and an organic light emitting layer, etc.

The first lines L1 may connect the driver and the pixels PXL. The linesLP may include gate lines GL, data lines DL, driving voltage lines DVLand power lines, etc. In an exemplary embodiment, the lines forming thelines LP may be data lines, but without limitation, that is, the linesforming the lines LP may of course vary.

The first lines L1 may be made of metal. For example, the first lines L1may be made of metal of at least one of gold (Au), silver (Ag), aluminum(Al), molybdenum (Mo), chrome (Cr), titanium (Ti nickel (Ni), neodynium(Nd), and copper (Cu), or an alloy thereof. Further, the first lines L1may each be formed as a single layer line, but without limitation, thatis, the first lines L1 may each be formed as a line consisting ofmultiple layers where two or more of the aforementioned metals andalloys thereof are laminated. However, the material of the first linesL1 is not limited to the aforementioned. In an exemplary embodiment,additional lines necessary for driving the pixels PXL may be provided inthe non-display area NDA besides the data line(s) aforementioned.

The first lines L1 may extend from the pixels to an end of theadditional area ADA in the second direction DR2, and in the portionwhere the display panel DP and the chip on film COF overlap with eachother, the first lines L1 may generally extend in the second directionDR2, as illustrated.

At the end of the additional area ADA in the second direction DR2, eachof the lines L1 has first pads L1P provided at an end thereof. Each ofthe first pads L1P of the first lines L1 may have a width that is thesame as or greater than that of each of the first lines L1 connectedthereto. The first lines L1 may be connected to the driver realized onthe chip on film COF and/or printed circuit board PCB through the firstpads L1P.

The chip on film COF may be connected to an end of the display panel DP,and connects the pixels PXL in the display panel DP and the driver. Thechip on film COF may include an insulating film ISF and the second linesL2 provided on the insulating film ISF. The chip on film COFcollectively refers to the insulating film made of a thin film and thelines formed on the insulating film. The chip on film COF may bereferred to as a tape carrier package, a flexible printed circuit boardor the like.

Although not illustrated, in the chip on film COF, besides the secondlines L2, the insulating film ISF may be further provided with asemiconductor chip connected to at least a portion of the second linesL2. The semiconductor chip may be at least a portion of the driver.

The insulating film ISF has a first surface SF1 and a second surface SF2that are opposite to each other, the second lines L2 being disposed onthe first surface SF1.

The insulating film ISF may be made of an insulating material. Thesubstrate SUB may be made of an insulating material such as glass andresin, etc. Further, the substrate SUB may be made of a flexiblematerial so that it may be bent or folded, and the substrate SUB mayhave a structure of a single layer or a structure of multiple layers.

For example, the substrate SUB may include at least one of polystyrene,polyvinyl alcohol, polymethyl methacrylate, polyethersulfone,polyacrylate, polyetherimide, polyethylene naphthalate, polyethyleneterephthalate, polyphenylene sulfide, polyarylate, polyimide,polycarbonate, triacetate cellulose and cellulose acetate propionate.However, the material forming the substrate SUB may vary. For example,the substrate SUB may be made of fiber reinforced plastic FRP and thelike.

At one end of each of the second lines L2, a second pad L2P may beprovided. The second pads L2P of the second lines L2 may each have awidth that is the same as or greater than that of each of the secondlines L2. FIGS. 4A and 5B illustrate that each of the second pads L2P ofthe second lines L2 is formed to have the same width as that of each ofthe second lines L2, but there is no limitation thereto.

The first surface SF1 of the chip on film COF may be arranged in adirection facing the display panel DP. The second lines L2 maycorrespond to the first lines L1 one by one, and the first lines L1 andthe second lines L2 face each other. In a plan view, each of the firstpads L1P of the first lines L1 and each of the second pads L2P of thesecond lines L2 may overlap with each other. Assuming that the width ofeach of the first pads L1P of the first lines L1 is a first width W1 anda width of each of the second pads L2P of the second lines L2 is asecond width W2, the first width W1 and the second width W2 have valueslarge enough for each of the first pads L1P and each of the second padsL2P to overlap with each other. The first width W1 and the second widthW2 may be identical to or different from each other. In the drawings ofthe embodiments of the present disclosure, the first width W1 isillustrated to be greater than the second width W2, but there is nolimitation thereto, that is, the second width W2 may be greater than thefirst width W1.

In an exemplary embodiment, in a plan view, the second pads L2P arespaced apart from the edge of the insulating film ISF. That is, thesecond pads L2P do not contact the edge of the insulating film ISF, andthe second pads L2P are not formed within an area of a certain distanceD from the edge.

The second lines L2 may be made of metal just as the first lines. Forexample, the second lines L2 may be made of metal of at least one ofgold (Au), silver (Ag), aluminum (Al), molybdenum (Mo), chrome (Cr),titanium (Ti), nickel (Ni), neodynium (Nd), and copper (Cu), or an alloythereof. Further, the second lines L2 may each be made of a singlelayer, but without limitation, that is, the second lines L2 may each bemade of multiple layers where two or more of the aforementioned metalsand alloys thereof are laminated. However, the material of the secondlines L2 is not limited thereto.

The chip on film COF may be produced in a method for forming the secondlines L2 made of metal on the insulating film ISF. Examples of themethod for forming the second lines L2 include a casting method, alaminating method, and an electrogliding method, etc.

The anisotropic conductive film ACF may be provided between the displaypanel DP and the chip on film COF to connect the display panel DP andthe chip on film COF. The anisotropic conductive film ACF may beprovided between the first pads L1P of the first lines and the secondpads L2P of the second lines L2, in a cross-sectional view. In a planview, the anisotropic conductive film ACF may overlap with the pads ofthe chip on film COF. The anisotropic conductive film ACF may also beprovided such that it is spaced by a certain distance from the edge ofthe insulating film ISF.

The anisotropic conductive film ACF may include an organic polymer and aplurality of conductive balls inside the organic polymer.

The organic polymer may be a curable resin that has adhesiveness andthat is curable by heat or light. The curable resin may be made of athermosetting resin. Examples of the thermosetting resin that may beused herein include bisphenol A type epoxy resin, bisphenol F typeresin, novolak type epoxy resin, phenol resin, urea resin, melamineresin, unsaturated polyester resin, resorcinol resin and the like, butwithout limitation. The organic polymer may also be made of athermoplastic resin. Examples of the thermoplastic resin that may beused herein include saturated polyester resin, vinyl resin, acryl resin,polyolefin resin, polyvinylacetate PVA resin, polycarbonate resin,cellulose resin, ketone resin, sytrene resin and the like, but withoutlimitation.

The conductive balls may be made of metal such as gold, silver, tin,nickel chrome, iron, cobalt, platinum, and copper and an alloy thereof.Alternatively, the conductive balls may be made of a core that includesglass, ceramic or polymer resin, and the aforementioned metal or alloythereof formed on the core surface.

The anisotropic conductive film ACF may be provided between the firstpads L1P and the second pads L2P. When the first pads L1P and the secondpads L2P are compressed, the first pads L1P and the second pads L2P areelectrically connected through the conductive balls.

The coating layer CL may be provided at one end of the display panel DPand the chip on film COF, thereby covering the one end of the displaypanel DP and the chip on film COF. In the present embodiment of thepresent disclosure, the coating layer CL is illustrated as being formedas a single layer, but without limitation, that is, the coating layer CLmay be formed to have a structure of multiple layers including two ormore layers.

The coating layer CL may control a point to which a stress is to beapplied within the display panel DP when the display panel DP is beingbent. This will be explained in more detail later on.

The coating layer CL may be filled between a first area R1 of the chipon film COF and the display panel DP. Assuming that the area of the chipon film COF contacting the end of the insulating film but overlappingwith the anisotropic conductive film ACF is a first area R1, and thearea of the chip on film COF not overlapping with the anisotropicconductive film ACF is a second area R2, the coating layer CL is filledin the second area R2.

By covering the end of the display panel DP and the chip on film COF,the coating layer CL may serve the function of preventing the chip onfilm COF from being corroded. The coating layer CL is provided at theend side of the chip on film COF, so that it covers a portion and a sidesurface of the second surface SF2 of the insulating film, and a portionof the first surface SF1 of the insulating film. Especially, the coatinglayer CL may be filled between the chip on film COF and the displaypanel DP, thereby preventing external moisture or oxygen frominfiltrating into the second lines L2 of the chip on film COF. Further,the coating layer CL may serve the function of firmly attaching thedisplay panel DP and the chip on film COF, preventing the chip on filmCOF from deviating from the display panel DP even when stress is appliedto the display panel DP caused by bending.

The coating layer CL may be made of a curable resin that is curable byheat or light. In an exemplary embodiment, the coating layer CL is aphotosetting material. Examples of the curable resin that may be usedherein include bisphenol A type epoxy resin, bisphenol F type resin,novolak type epoxy resin, phenol resin, urea resin, melamine resin,unsaturated polyester resin, resorcinol resin and the like, but withoutlimitation. The coating layer CL may also be made of a thermoplasticresin. Examples of the thermoplastic resin that may be used hereininclude saturated polyester resin, vinyl resin, acryl resin, polyolefinresin, polyvinylacetate PVA resin, polycarbonate resin, cellulose resin,ketone resin, sytrene resin and the like, but without limitation.

A solder resist layer SR may be provided on the first surface SF1 of theinsulating film. The solder resist layer SR may cover the first surfaceSF1 of the insulating film and the second lines L2 excluding the secondpads L2P, thereby protecting the second lines L2.

The solder resist layer SR is not formed on the end of the chip on filmCOF. In an exemplary embodiment, in a plan view, the solder resist layerSR partially overlaps with the display panel DP.

The solder resist layer SR may be made of a curable resin that iscurable by heat or light. Examples of the curable resin that may be usedherein include bisphenol A type epoxy resin, bisphenol F type resin,novolak type epoxy resin, phenol resin, urea resin, melamine resin,unsaturated polyester resin, resorcinol resin and the like, but withoutlimitation. The solder resist layer SR may also be made of athermoplastic resin. Examples of the thermoplastic resin that may beused herein include saturated polyester resin, vinyl resin, acryl resin,polyolefin resin, polyvinylacetate PVA resin, polycarbonate resin,cellulose resin, ketone resin, sytrene resin, epoxy acryl resin,polyester acryl resin, urethane acryl resin and the like, but withoutlimitation.

In an exemplary embodiment, the solder resist layer SR may be made of amaterial that is the same as or different from that of the coating layerCL.

Additionally, in the area where the chip on film COF and the displaypanel DP overlap with each other, the end of the display panel DP may beprovided with an additional coating layer ACL. The additional coatinglayer ACL may cover the side surface of the display panel and a portionof the solder resist layer SR formed on the chip on film COF. Theadditional coating layer ACL prevents moisture or oxygen frominfiltrating into the area where the chip on film COF and the displaypanel DP are connected. The material of the additional coating layer ACLmay be the same as or different from the material of the coating layerCL. According to embodiments, the material forming the additionalcoating layer ACL may vary.

FIG. 6 is a cross-sectional view illustrating the display deviceaccording to an exemplary embodiment of the present disclosure.

Referring to FIG. 6, the display device according to an exemplaryembodiment may further include a polarizing plate POL provided on thefront surface of the display panel, a window WD provided on the frontsurface of the polarizing plate POL, a cushion member CS providedbetween the display panel DP and the chip on film COF, and a cover CVfor receiving the display panel DP, the polarizing plate POL and thewindow WD, besides the display panel DP, the chip on film COF, and theprinted circuit board PCB.

The display panel DP displays an image in the front surface direction,and the display panel DP may be bent in the bending area BA. In anexemplary embodiment, the display panel DP may be provided with thefirst flat area FA1 and the second flat area FA2 that are spaced apartfrom each other with the bending area BA disposed therebetween, and thefirst flat area FA1 and the second flat area FA2 may be arrangedparallel to each other with the bending area BA disposed therebetween.

One end of the chip on film COF may be connected to one end of thedisplay panel DP, for example, to one end of the second flat area FA2.

A portion of the display panel DP and a portion of the chip on film COFmay be covered by the coating layer CL. The coating layer CL maysubstantially cover an entirety of an outer circumference of the bendingarea BA of the display panel DP, and the coating layer CL may extend upto a portion of the first and second flat area FA1, FA2.

The coating layer CL may be made of a curable organic polymer, and thecoating layer CL is provided on an upper surface of the display panel DPto have a certain thickness, thereby functioning as a neutral planeadjusting element.

In an exemplary embodiment, in the case where a portion of the displaydevice is being bent, having a certain surface between an inner surfaceand an outer surface of the display device as a boundary, the innersurface may be compressed, providing a compressive force, and an outersurface of the display device is tensed, providing a tensile force. Aneutral plane NP is a surface where a vector sum of the tensile forceand the compressive force is zero (0) when the display panel DP is beingbent. Therefore, in the neutral plane NP, the bending strain caused bythe bending stress applied to the display panel DP becomes zero (0).

The location of the neutral plane NP is determined by the thickness andthe modulus of elasticity of each of the layers forming the displaypanel DP. The layers include the substrate SUB, the first lines L1 andthe coating layer CL. That is, by changing the thickness and/or themodulus of elasticity of the coating layer CL in consideration of thethickness and the modulus of elasticity of the first lines L1, it ispossible to adjust the location of the neutral plane NP. In an exemplaryembodiment, by changing the thickness and/or the modulus elasticity ofthe coating layer CL, in particular, it is possible to place the neutralplane NP on the upper surface of the substrate, that is in an area wherethe first lines L1 are arranged.

For example, although the coating layer CL is illustrated as having asubstantially identical thickness throughout the entirety of the bendingarea, there is no limitation thereto, that is, In an exemplaryembodiment, the thickness of the coating layer CL may vary throughoutthe entirety of the bending area. In another exemplary embodiment, thecoating layer CL may be made of different materials but have a uniformthickness throughout the entirety of the bending area. In yet anotherexemplary embodiment, the coating layer CL may be made of multiplelayers having different modulus of elasticity or different thicknessesthroughout the entirety of the bending area.

As aforementioned, in the case where the coating layer CL is notprovided on the display panel DP, the neutral plane NP may be disposedin a different location from the first lines L1, but in the case wherethe coating layer CL is provided on the display panel, especially on thefirst lines L1, the neutral plane NP may be disposed in the samelocation as the first wires L1. As a result, deformation of the lines L1may be minimized even when a bending stress occurs in the display panel.Accordingly, the first lines L1 may not crack or be disconnected anddefects may not occur in the display device.

The printed circuit board PCB may be connected to another end of thechip on film COF, and the printed circuit board PCB may be disposed onthe rear direction of the first flat area FA1.

The polarizing plate POL may be provided on the front surface of thedisplay panel DP, that is, on the display area, having an adhesivetherebetween. The polarizing plate POL may prevent external light frombeing reflected. In the present embodiment of the present disclosure,the polarizing plate POL is provided, but without limitation, that is,the polarizing plate may be substituted for another type of opticalfilm. Otherwise, another type of optical film may be provided inaddition to the polarizing plate POL.

Although not illustrated in the drawings, a touch sensor may be furtherprovided between the polarizing plate POL and the display panel DP. Inan exemplary embodiment, the touch sensor may be provided not betweenthe polarizing plate POL and the display panel DP, but inside thedisplay panel DP.

The window WD may be provided on the polarizing plate POL to protect tothe display panel DP. The window WD may be made of a transparentinsulating material such as glass and organic polymer, etc. The windowWD may be formed to have the same surface area as or a different surfacearea from that of the display area.

The cushion member CS may be provided on the rear surface of the displaypanel DP to buffer the impact being applied to the display panel DP. Inan exemplary embodiment, the cushion member CS may be provided betweenthe first flat area FA1 and the second flat area FA2 of the displaypanel DP.

The cushion member CS may be provided as a porous polymer so as to haveelasticity. For example, the cushion member CS may be made of foam suchas sponge.

For example, the cushion member CS may include thermoplastic elastomer,polystyrene, polyolefin, polyurethane thermoplastic elastomers,polyamides, synthetic rubbers, polydimethylsiloxane, polybutadiene,polyisobutylene, poly(styrene-butadienestyrene, polyurethanes,polychloroprene, polyethylene, silicone, or a combination thereof, butwithout limitation.

The cover CV may receive the cushion member CS provided between thedisplay panel DP and the chip on film COF, the display panel DP, thepolarizing plate POL, the window WD, and the like into a lower surfaceand a side surface of the cover CV.

FIGS. 7A, 7B, and 7C are cross-sectional views sequentially illustratinga process of attaching the display panel DP and the chip on film COF inthe display device according to an exemplary embodiment of the presentdisclosure.

Referring to FIG. 7A, the display panel DP and the chip on film COF areprepared.

The display panel DP may be produced by preparing the substrate SUB, andthen forming the first lines L1 on the substrate SUB.

The chip on film COF may be produced by preparing the insulating filmISF and forming the second lines L2 on the insulating film ISF. In thechip on film COF, portions excluding the second pads are covered by thesolder resist SR.

Next, the anisotropic conductive film ACF may be disposed between thedisplay panel DP and the chip on film COF. The display panel DP and thechip on film COF may be disposed such that the first lines L1 and thesecond lines L2 face each other having the anisotropic conductive filmACF disposed therebetween.

The display panel DP, the anisotropic conductive film ACF and the chipon film COF may be compressed by a certain pressure P using acompressing device. The compressing device may include a compressingmember PS and a buffer member BF that surrounds the compressing memberPS. The compressing member PS may further include a heating device, andwhen compressing the display panel DP, the anisotropic conductive filmACF and the chip on film COF with the compressing device, heat may betransferred to the anisotropic conductive film ACF. With the heattransferred from the compressing device, the organic polymer of theanisotropic conductive film ACF may be cured. Accordingly, by thecompressing device, the display panel DP and the chip on film COF areattached having the anisotopic conductive film ACF disposedtherebetween.

Next, referring to FIG. 7B, the coating layer CL may be formed on theattached display panel DP and the chip on film COF. In an exemplaryembodiment, the coating layer CL may be formed by applying a non-curedor semi-cured organic material on the display panel DP and the chip onfilm COF using a slit SLT. However, the method for forming the coatinglayer CL on the display panel DP and the chip on film COF is not limitedto the aforementioned, that is, other well known methods for forming anon-cured or semi-cured organic material may be used instead.

By applying a fluid state coating layer CL on the display panel DP andthe chip on film COF, the coating layer CL may be filled between thedisplay panel DP and the chip on film COF.

In an exemplary embodiment, after forming the coating layer CL using thenon-cured or semi-cured organic material, the additional coating layerACL may be formed.

Referring to FIG. 7C, light (for example, ultraviolet UV light) may beapplied to the coating layer CL and the additional coating layer ACL,thereby curing the coating layer CL and the additional coating layerACL.

Although it is illustrated in the aforementioned drawings that thecoating layer CL is formed and cured in a state where the display panelDP is not bent according to an exemplary embodiment, this is not meantas a limitation. For example, the coating layer CL may be formed andcured in a state where the display panel DP is bent. Alternatively, thecoating layer CL may be formed in a state where the display panel DP isnot bent, and then cured after the display panel DP is bent.

In the display device produced in the aforementioned method, the displaypanel DP may be bent in the bending area, and then assembled togetherwith the polarizing plate POL, the window WD, the cushion member CS andthe cover, etc.

In the display device according to an exemplary embodiment, the pads ofthe chip on film COF may be provided in various forms.

FIGS. 8A and 8B are plan views illustrating the second pads L2 p of thechip on film COF.

Referring to FIGS. 8A and 8B, according to an exemplary embodiment ofthe present disclosure, the second pads L2P of the chip on film COF maysequentially have a third width W2 a and a fourth width W2 b that aredifferent from each other in a direction moving away from the edge ofthe insulating film ISF. In an exemplary embodiment, in the second padsL2P, assuming that the width of the second pads L2P farther away fromthe edge of the insulating film ISF is the third width W2 a and thewidth of the second pads L2P closer to the edge of the insulating filmISF is the fourth width W2 b, the fourth width W2 b may be smaller thanthe third width W2 a.

Regarding the second pads L2P, the closer it is to the edge of theinsulating film ISF, the smaller its width, and thus extra organicpolymer may be easily squeezed out when attaching the display panel DPand the chip on film COF.

In the display device according to an exemplary embodiment, the solderresist layer SR (see FIG. 7C) may be provided in various forms.

FIG. 9 is a cross-sectional view of the display device according to anexemplary embodiment of the present disclosure, where the solder resistlayer SR is formed differently.

According to an exemplary embodiment, the solder resist layer SR may beprovided so as to not overlap with the display panel DP in a plan view.The shape and the location of the solder resist layer SR may vary aslong as it protects the second lines L2.

According to the aforementioned exemplary embodiment, as the second padsL2P are spaced apart from the edge of the insulating film and the secondlines L2 are prevented from being corroded. In the case where the secondlines L2 contact the edge of the insulating film, if moisture or oxygeninfiltrates from outside, the second lines L2 may be easily corroded,which is a problem. However, according to the exemplary embodiments ofthe present disclosure, the second pads L2P do not directly contact theedge of the insulating film, and the space from the edge of theinsulating film to the end of the second lines L2 may be covered by thecoating layer CL, and thus the second lines L2P are prevented from beingcorroded.

Thus, according to the aforementioned embodiments, lines of a chip onfilm may be prevented from being corroded as they are spaced apart froman edge of an insulating film.

The display device according to an embodiment of the present disclosuremay be adopted to various kinds of electronic devices. For example, thedisplay device may be applied to various wearable devices such as TV,notebook, mobile phone, smart phone, smart pad, PMP, PDA and navigation,etc.

Although certain exemplary embodiments and implementations have beendescribed herein, other embodiments and modifications will be apparentfrom this description. Accordingly, the inventive concept is not limitedto such embodiments, but rather to the broader scope of the presentedclaims and various obvious modifications and equivalent arrangements.

What is claimed is:
 1. A display device, comprising: a display panelcomprising a substrate, pixels provided on the substrate, and firstlines connected to the pixels, wherein the display panel comprises abending area where the display panel is bent; a chip on film overlappingwith a portion of the display panel and comprising second lines; ananisotropic conductive film provided between the chip on film and thedisplay panel to connect the first lines and the second lines; and acoating layer covering the bending area and one end of the chip on film.2. The display device according to claim 1, wherein the first lines areprovided on a neutral plane.
 3. The display device according to claim 1,wherein the chip on film comprises: an insulating film comprising afirst surface and a second surface that are opposite to each other; thesecond lines are disposed on the first surface; and pads are disposed oneach end of the second lines, wherein the pads are spaced apart from anedge of the insulating film in a plan view.
 4. The display deviceaccording to claim 3, wherein the anisotropic conductive film overlapswith the pads of the chip on film, and is spaced apart from the edge ofthe insulating film in a plan view.
 5. The display device according toclaim 4, wherein the chip on film comprises a first area that contactsan end of the insulating film but does not overlap with the anisotropicconductive film and a second area that overlaps with the anisotropicconductive film, and wherein a space between the first area of the chipon film and the display panel is filled by the coating layer.
 6. Thedisplay device according to claim 3, wherein the pads have a first widthand a second width positioned sequentially in a direction moving awayfrom the edge of the insulating film.
 7. The display device according toclaim 6, wherein the first width and the second width are different fromeach other.
 8. The display device according to claim 7, wherein thefirst width is smaller than the second width.
 9. The display deviceaccording to claim 3, wherein the coating layer covers a portion of thesecond surface of the insulating film.
 10. The display device accordingto claim 9, further comprising a solder resist layer that is disposed onthe first surface of the insulating film and covers at least a portionof the second lines.
 11. The display device according to claim 10,wherein the solder resist layer overlaps with the display panel in aplan view.
 12. The display device according to claim 10, wherein thesolder resist layer does not overlap with the display panel.
 13. Thedisplay device according to claim 1, wherein the display panel comprisesa display area where the pixels are provided and a non-display areadisposed on at least one side of the display area, and the bending areacorresponds to the non-display area.
 14. The display device according toclaim 13, wherein the non-display area comprises an additional areaprotruding from a portion of the non-display area, and the display panelis bent in the additional area.
 15. The display device according toclaim 14, wherein the one end of the chip on film overlaps with theadditional area.
 16. The display device according to claim 15, furthercomprising a printed circuit board connected to another end of the chipon film.
 17. The display device according to claim 16, wherein thedisplay panel comprises a first flat area that comprises the displayarea, and a second flat area that is spaced apart from the first flatarea comprising the bending area disposed between the first flat areaand the second flat area, and wherein the first flat area and the secondflat area are parallel to each other.
 18. The display device accordingto claim 17, wherein the coating layer covers an outer circumference ofthe display panel in the bending area.
 19. The display device accordingto claim 18, wherein the coating layer covers a portion of the firstflat area and the second flat area.
 20. The display device according toclaim 1, wherein the coating layer comprises a photosetting material.